The Serotonin Club, founded in 1987, is an international association for biomedical scientists who are interested in research on any aspect of serotonin. An important objective of the Club is to facilitate the involvement of young investigators, comprising students, post-doctoral fellows and junior researchers (less than 3 years past their post-doctoral fellowship) in an international high-quality scientific meeting with serotonin as its central theme. Serotonin has been implicated in substance abuse, pain, cardiovascular and gastrointestinal function, neural development as well as a host of psychiatric diseases, including addiction. A diverse audience is attracted by including not only the neuroscience of serotonin, and the neurotransmitter systems on which it impinges, but also the role of serotonin in peripheral function. Thus, our goal is to bring together researchers with a common interest in serotonin such that the depth of its functions, and importantly, new discoveries, can be communicated. A new initiative of the Serotonin Club Meetings is to provide a focus and build a strong emphasis on substance abuse, as it relates to serotonin's interactions with other neurotransmitter systems, and importantly, to understand serotonin's role in the disease of addiction and how this system can be targeted for the treatment of substance abuse. A key goal of the 2012 meeting will be to foster this new initiative by inclusion of symposia directly related to substance abuse. Importantly, a major goal of the Serotonin Club is to provide a dynamic forum to help develop the careers of young investigators in the field. As such, we plan to include ten recipients of NIDA Travel Awards as featured speakers, one in each of ten programmed symposia. In addition these young investigators will i) be part of a mentoring program, ii) be able to network with senior researchers, including leaders in the field, at many occasion (e.g. poster sessions, breaks, lunches, and dinner banquet); and iii) have their work published in the conference proceedings. Selection will be based on the applicant's credentials and on the relevance of their abstract to drug abuse and related disorders. The first meeting of the Serotonin Club for which funds are sought will be held July 10-12, 2012 in Montpellier, France. The primary aim of this R13 application is to provide financial support to these young investigators to enable them to attend and participate in the 2012 Serotonin Club Meeting as well as to support future young investigators to attend subsequent meetings in 2014 and 2016.